Multiverse (meta-universe)

The multiverse is a theoretical concept that the universe as perceived by humans is just one of many universes—perhaps an infinite number—that exist in reality. Also known as parallel universes, the meta-universe, or the Many Worlds theory, the idea has long been a staple of science fiction. Scientists, however, believe multiple universes may be a very real possibility and have cited evidence for their existence. Theories on the multiverse range from matching universes arranged like a patchwork quilt to bubble-shaped universes bumping into one another. One exotic idea holds that each choice made by humans in this universe creates an alternate branch of existence where a different choice becomes the reality. In that scenario, alternate earths may exist where the dinosaurs did not become extinct or Christopher Columbus did not sail to the New World.

Background

According to the big bang theory, the most widely accepted explanation about the origin of the cosmos, the universe was created about 13.7 billion years ago in an enormous explosion. At the time, all the matter in the universe was packed together in an incredibly small point called a singularity. In a space of time measured in billionths of seconds, the universe blew apart in an incredibly hot flash and began expanding in all directions. The first subatomic building blocks of matter—protons, neutrons, and electrons—were created in that flash. After about 380,000 years, the white-hot infant universe began to cool enough to form atoms. The first stars and galaxies were formed after about 400 million years. The Sun, Earth, and the rest of our solar system formed about 4.6 billion years ago—about 9 billion years after the big bang.

The earliest human attempts to understand the universe placed Earth at the center of all existence. It was not until the sixteenth century that Polish astronomer Nicolaus Copernicus deduced that Earth revolved around the Sun and not the other way around. Several decades after Copernicus developed his revolutionary idea, Italian philosopher Giordano Bruno proposed that the universe was infinitely large and contained an infinite number of inhabited worlds. Bruno was burned at the stake for such heresy, but by the eighteenth century, science had advanced to such a point that his idea of an immense cosmos containing many worlds was widely accepted. In the early twentieth century, Irish physicist Edmund Fournier d'Albe suggested the idea that the universe may be just one of many, each "nesting" inside one another and progressing from the unimaginably large to the infinitesimally small.

Overview

While d'Albe's idea is almost certainly incorrect, scientists do not dismiss the concept of multiple universes. In fact, many see evidence that the multiverse may not only be possible, but also that it is highly probable. The shape and form of such a multiverse is the subject of much speculation and for the moment exists only in scientific theory.

One of the more popular concepts of the multiverse assumes that the universe is unending and continues for infinity. Because the atoms that make up matter can only be arranged in a finite number of ways, in an infinite universe it is inevitable that matter will eventually begin repeating itself. In this scenario, countless universes must exist with identical Earths containing the same people, structures, societies, governments, etc., as our Earth. Constrained by the finite speed of light—186,000 miles per second—humans only have the capability of seeing to a certain point at the edge of the universe. Anything beyond that boundary would remain invisible and essentially would be another universe. These multiple universes would be laid out in a pattern like a giant patchwork quilt extending for infinity.

Another theory proposes that the universe did not expand in a uniform manner at the time of the big bang. Instead, some parts of the early universe inflated in fits and spurts at a faster rate than other parts. Each of the expanding pockets formed its own "bubble" universe. The universe humans perceive may have stopped expanding, but other bubbles may still be growing and forming completely new universes with different laws of physics. Some scientists suggest these alternate bubble universes exist outside three-dimensional space and can encounter other universes. If this were to happen, it could cause a cataclysmic event that would destroy both universes and initiate another cosmic big bang.

Evidence for another type of multiverse is seen in the seemingly bizarre behavior of subatomic particles involved in the science of quantum physics. While protons, neutrons, and electrons are the construction materials that make up atoms, each of those particles is itself made up of smaller, more mysterious particles. Through indirect experimentation, scientists have proven that these particles can exist in more than one physical location at the same time. Once the particle is actually observed, however, the phenomenon ends in what is known as wave function collapse. In the 1950s, American physicist Hugh Everett proposed the reason this happens is that upon observation, the particle "chooses" a particular state in which to exist. The other states branch off and exist in other realities in other universes.

Everett's Many Worlds theory was later expanded on to allow for an immense number of parallel universes with many possible realities. Each time an electron takes a particular path, another universe is instantaneously created in which the electron took the opposite path. The theory also holds that each decision a person makes in life creates a "fork" in reality, creating two or more alternate universes. In one universe, the original decision becomes reality, while in the others different choices are made. If this theory were true, multiple universes would exist, each with a different version of reality.

For each set of possible outcomes from a specific decision, the theory suggests an alternate universe must exist in which one of those other outcomes became reality. For example, if a person met their future spouse on a blind date, an alternate reality must exist where the person decided to skip that date, married someone else, and had a different set of children. This also means that there must be other universes with drastically different historical timelines. In one, the British would have won the Revolutionary War (1775–1783) and the United States would never have become an independent nation. In others, humans would not have landed on the moon, computers would never have been invented, or World War III would have occurred in the 1960s.

Bibliography

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